Fiona Gill

Dr Fiona Gill

Research Fellow

Organisation

University of Leeds

Research summary

My fellowship research focuses on the chemistry of modern and fossilised faeces (coprolites). Faeces contains a complex mixture of chemical compounds, including substances from the diet and digestive processes. However, the faecal molecules I am most interested in come from microbes that live symbiotically within the digestive tract of herbivorous animals, such as methanogenic archaea. These microbes, which produce methane as a by-product of fermentation of plant material, have cell membranes containing a distinctive molecule called archaeol. I am currently investigating the relationship between the concentration of archaeol in faeces and the amount of methane emitted by animals. This could potentially be developed as a new method for quantifying methane emissions from modern domesticated and wild ruminants, which are estimated to produce up to one fifth of global emissions of methane, a greenhouse gas known to contribute to climate change. If successful, the same approach could be used to analyse coprolites from Ice Age animals such as woolly mammoths, giant sloths and bison, or even more ancient animals such as dinosaurs, to find out which ones produced methane and possibly how much. By better understanding the biology of extinct animals we can gain insights into how they interacted with their environment and potentially why they became extinct.

Other research also focuses on chemical evidence for symbiosis between microbes and animals in the fossil record, for example the relationship between bacteria and clams, mussels and other shellfish living at sites of sea floor methane seepage. Analysis of the small amounts of organic matter preserved in fossil shells may indicate whether the ancient animals were filter feeders or derived their nutrition from symbiotic bacteria.